This invention relates to pet food, and more particularly to bulk packaged mixtures of hard and soft pet food in which the hard pieces are of the "dry" pet food type, and the soft pieces are either "dry" or "semi-moist" pet food.
Within the class of pet foods, there are three basic categories: (1) dry pet food; (2) semi-moist pet food; and (3) moist pet food.
Generally speaking, each pet food of a particular category differs from the other pet food categories in that different packaging techniques are required and different palatability levels are achieved. The dry pet food contains the least amount of moisture and is the most stable. Therefore, the dry pet food requires the least sophisticated packaging, and is the simplest to handle and store. Whereas the dry pet foods contain up to about 15 percent moisture by weight and are the most stable of the three classes of pet foods, the semi-moist pet food contains an intermediate range of moisture, namely about 15 to about 50 percent by weight moisture. The semi-moist pet food requires somewhat more sophisticated packaging than does the dry pet food, but does not have to be sterile at the time of packaging. The semi-moist pet foods do not require aseptic canning, and are stable when wrapped in a standard polyethylene package or other conventional package. The so-called moist pet foods contain more than about 50 percent by weight moisture and require aseptic canning conditions to stabilize the pet food for marketing purposes. The moist pet foods are generally rated as highly palatable and the semi-moist pet foods are generally speaking, rated as more palatable than the dry pet foods.
Hard, dry pet food, while being very stable and easiest to store and handle, and being particularly suitable for shipping, storing and feeding in large packages, e.g. for most economical maintenance of relatively large pets, for example, has been regarded heretofore, as not as palatable as the other classes of pet food. Thus, although dry pet food is very nutritional, in some cases it was not a particularly acceptable pet food to either the pet or the pet owner. Although proper nutrition is provided by the hard, relatively abrasive pet food, the pet does not necessarily accept this food due to the hard abrasive nature. Yet, in many cases, the hard abrasive nature is highly desirable for teeth cleaning characteristics in addition to the nutritional aspects, and ease of shipping and storing. Consequently, in spite of all its inherent advantages, it may be difficult to feed a hard dry pet food because of the palatability and other acceptance problems.
In a recent U.S. Pat. No. 4,039,689 issued to David Palmer Bone on Aug. 2, 1977, a highly nutritional soft dry pet food was disclosed. In another U.S. Pat. No. namely 4,006,266 issued on Feb. 1, 1977 to David Palmer Bone and Edward Leo Shannon, a process for making a dry pet food having a hard component and a soft component was disclosed. The soft dry pet foods have all the highly advantageous storing and handling characteristics of the hard dry pet foods, and yet have proven to be much more acceptable both to the pet and to the pet owners because of the greater palatability of the soft dry pet foods as compared to the hard dry pet foods. The disclosure in U.S. Pat. No. 4,006,266, although specifically directed to "dry" pet food, i.e. those having a moisture content less than 15 percent by weight and typically about 10 percent by weight, refers to the increased palatability resulting from providing mixtures of the hard and soft pet foods instead of products consisting solely of hard dry pieces.
The Bone and Shannon U.S. Pat. No. 4,006,266 discloses the admixing of pieces of soft meat-like dry dog food with pieces of hard dry pet food. In one embodiment, the 4,006,266 patent refers to the production of the soft component as a stranded or "burger form" but states that it is desirable to refrain from cutting the strands after extrusion, and to use the attrition prevailing during the blending of the soft component strands with the hard component pieces to effect the breakup of strands into shorter pieces.
The dry pet foods are most desirable and advantageous for use in the simple, economically packaged "large package" segment of the pet food market, e.g. that sold in bulk in 5, 10, 20, and 40 pound bags. Several serious problems have been experienced, however, in the distribution, marketing and use of bulk packaged combinations of hard and soft dry pet foods as heretofore described.
It has been found that when a mixture of bite-sized soft and hard pet foods were packaged, stored and shipped in such large bags (e.g. 5, 10, 20 or 40 pounds per bag) on pallets and the like, the compression due to weight of the product resulted in a tendency for the contents of the bags to undergo "chunking", that is, adhesion between the soft and hard pieces. This resulted in the formation of larger composite chunks and an undesirable diminishment of the free flowing, discrete-particle characteristic of the pet food. On the other hand, when, as taught in Bone U.S. Pat. No. 4,006,266 the long strands of the "burger form" are extruded onto a conveyor belt and are broken up by the blending of the soft component strands with the hard component pieces so much breakage results in substantial product separation. Uncontrolled breakage, and production of small fragments of the soft portion of the product results in a very serious tendency of the product mixture to separate with the smaller fragments migrating downwardly under the influence of gravity, vibration, and product movement.
Such separation of the hard and soft components of the mixture obviously destroys the integrity of the product concept, i.e. a relatively uniform mixture of the hard and soft pet food pieces.
An object of the present invention is to provide a product mixture of hard and soft pet foods suitable for bulk packaging, in which the hard pet food is of the "dry" category and the soft pet food can be selected from either the "dry" or "semi-moist" category, which product when packaged bulk, results in substantially no chunking, minimal breakup of pieces, and substantially no product separation.